Actions for selected content:

Send content to

To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .

To send content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services
Please confirm that you accept the terms of use.

First-degree relatives of patients with psychotic disorder have higher levels of polygenic risk (PRS) for schizophrenia and higher levels of intermediate phenotypes.

Methods

We conducted, using two different samples for discovery (n = 336 controls and 649 siblings of patients with psychotic disorder) and replication (n = 1208 controls and 1106 siblings), an analysis of association between PRS on the one hand and psychopathological and cognitive intermediate phenotypes of schizophrenia on the other in a sample at average genetic risk (healthy controls) and a sample at higher than average risk (healthy siblings of patients). Two subthreshold psychosis phenotypes, as well as a standardised measure of cognitive ability, based on a short version of the WAIS-III short form, were used. In addition, a measure of jumping to conclusion bias (replication sample only) was tested for association with PRS.

Results

In both discovery and replication sample, evidence for an association between PRS and subthreshold psychosis phenotypes was observed in the relatives of patients, whereas in the controls no association was observed. Jumping to conclusion bias was similarly only associated with PRS in the sibling group. Cognitive ability was weakly negatively and non-significantly associated with PRS in both the sibling and the control group.

Conclusions

The degree of endophenotypic expression of schizophrenia polygenic risk depends on having a sibling with psychotic disorder, suggestive of underlying gene–environment interaction. Cognitive biases may better index genetic risk of disorder than traditional measures of neurocognition, which instead may reflect the population distribution of cognitive ability impacting the prognosis of psychotic disorder.

We present a broad study of linear, clustered, noble gas puffs irradiated with the frequency doubled (527 nm) Titan laser at Lawrence Livermore National Laboratory. Pure Ar, Kr, and Xe clustered gas puffs, as well as two mixed-gas puffs consisting of KrAr and XeKrAr gases, make up the targets. Characterization experiments to determine gas-puff density show that varying the experimental parameter gas-delay timing (the delay between gas puff initialization and laser-gas-puff interaction) provides a simple control over the gas-puff density. X-ray emission (>1.4 keV) is studied as a function of gas composition, density, and delay timing. Xe gas puffs produce the strongest peak radiation in the several keV spectral region. The emitted radiation was found to be anisotropic, with smaller X-ray flux observed in the direction perpendicular to both laser beam propagation and polarization directions. The degree of anisotropy is independent of gas target type but increases with photon energy. X-ray spectroscopic measurements estimate plasma parameters and highlight their difference with previous studies. Electron beams with energy in excess of 72 keV are present in the noble gas-puff plasmas and results indicate that Ar plays a key role in their production. A drastic increase in harder X-ray emissions (X-ray flash effect) and multi-MeV electron-beam generation from Xe gas-puff plasma occurred when the laser beam was focused on the front edge of the linear gas puff.

The objectives of this paper are to: (1) identify contextual factors such as policy that impacted the implementation of community-based primary health care (CBPHC) innovations among 12 Canadian research teams and (2) describe strategies used by the teams to address contextual factors influencing implementation of CBPHC innovations. In primary care settings, consideration of contextual factors when implementing change has been recognized as critically important to success. However, contextual factors are rarely recorded, analyzed or considered when implementing change. The lack of consideration of contextual factors has negative implications not only for successfully implementing primary health care (PHC) innovations, but also for their sustainability and scalability. For this evaluation, data collection was conducted using self-administered questionnaires and follow-up telephone interviews with team representatives. We used a combination of directed and conventional content analysis approaches to analyze the questionnaire and interview data. Representatives from all 12 teams completed the questionnaire and 11 teams participated in the interviews; 40 individuals participated in this evaluation. Four themes representing contextual factors that impacted the implementation of CBPHC innovations were identified: (I) diversity of jurisdictions (II) complexity of interactions and collaborations (III) policy, and (IV) the multifaceted nature of PHC. The teams used six strategies to address these contextual factors including: (1) conduct an environmental scan at the beginning (2) maintaining engagement among partners and stakeholders by encouraging open and inclusive communication; (3) contextualizing the innovation for different settings; (4) anticipating and addressing changes, delays, and the need for additional resources; (5) fostering a culture of research and innovation among partners and stakeholders; and (6) ensuring information about the innovation is widely available. Implementing CBPHC innovations across jurisdictions is complex and involves navigating through multiple contextual factors. Awareness of the dynamic nature of context should be considered when implementing innovations.

The development of laser wakefield accelerators (LWFA) over the past several years has led to an interest in very compact sources of X-ray radiation – such as “table-top” free electron lasers. However, the use of conventional undulators using permanent magnets also implies system sizes which are large. In this work, we assess the possibilities for the use of novel mini-undulators in conjunction with a LWFA so that the dimensions of the undulator become comparable with the acceleration distances for LWFA experiments (i.e., centimeters). The use of a prototype undulator using laser machining of permanent magnets for this application is described and the emission characteristics and limitations of such a system are determined. Preliminary electron propagation and X-ray emission measurements are taken with a LWFA electron beam at the University of Michigan.

Species that belong to the Aphidius eadyi group have been used as biocontrol agents against Acyrthosiphon pisum worldwide. However, despite their extensive use, there are still gaps in our knowledge about their taxonomy and distribution. In this study, we employed an integrative taxonomic approach by combining genetic analyses (mtDNA COI barcoding) with standard morphological analyses and geometric morphometrics of forewing shape. We identified three species within the A. eadyi species group, viz., A. smithi, A. eadyi and A. banksae. Genetic separation of all three species was confirmed, with mean genetic distances between species ranging from 5 to 7.4%. The following morphological characters were determined as the most important for separating species of the A. eadyi group: number and shape of costulae on the anterolateral part of the petiole, shape of the central areola on the propodeum, and shape and venation of the forewings. The differences in wing shape of all three species were statistically significant, but with some overlapping. We identified A. banksae as a widely distributed pea aphid parasitoid, whose known range covers most of the western Palaearctic (from the UK to Israel). Aphidius banksae is diagnosed and redescribed.

At Nikolaev, in 1978, a system for the improvement in the stability of the light path between the transit instrument and the meridian mires was designed. Its purpose is to improve the accuracy of the azimuth determination and that of the collimation. This system consists of twelve sections of 8 mm thick steel tube with 160 mm diameter, each nine meters long. These tubes are lying in special steel cradles which rest on brick support columns spaced 8 meters apart, and these can be moved vertically and horizontally by 100 mm and 50 mm, respectively. Thus it is possible to align the axis of the tube exactly.

The present-day realization of inertial coordinate system by means of traditional optical astrometry is the Fifth Fundamental Catalogue (FK5). The series of observations with new meridian instruments (CAMC, PMC-190, BAMC, HMC) show the significant correlated differences (up to 0.″1) of observational catalogues from the FK5. Moreover, FK5 mean epoch appears to be old (about 50 years ago) and FK5 proper motions would have essential errors owing to the fact that not many new original catalogues (only 25 in RA and 15 in DEC) were used when compiling FK5. It should be noted also that FK5 has a dissimilar accuracy of positions and proper motions of “old” and “new” stars.

In order to compare estimates by one assessment scale across various cultures/ethnic groups, an important aspect that needs to be demonstrated is that its construct across these groups is invariant when measured using a similar and simultaneous approach (i.e., demonstrated cross-cultural measurement invariance). One of the methods for evaluating measurement invariance is testing for differential item functioning (DIF), which assesses whether different groups respond differently to particular items. The aim of this study was to evaluate the cross-cultural measurement invariance of the Revised Child Anxiety and Depression Scale (RCADS) in societies with different socioeconomic, cultural, and religious backgrounds.

Methods.

The study was organised by the International Child Mental Health Study Group. Self-reported data were collected from adolescents residing in 11 countries: Brazil, Bulgaria, Croatia, Indonesia, Montenegro, Nigeria, Palestinian Territories, the Philippines, Portugal, Romania and Serbia. The multiple-indicators multiple-causes model was used to test the RCADS items for DIF across the countries.

Results.

Ten items exhibited DIF considering all cross-country comparisons. Only one or two items were flagged with DIF in the head-to-head comparisons, while there were three to five items flagged with DIF, when one country was compared with the others. Even with all cross-culturally non-invariant items removed from nine language versions tested, the original factor model representing six anxiety and depressive symptoms subscales was not significantly violated.

Conclusions.

There is clear evidence that relatively small number of the RCADS items is non-invariant, especially when comparing two different cultural/ethnic groups, which indicates on its sound cross-cultural validity and suitability for cross-cultural comparisons in adolescent anxiety and depressive symptoms.

Differential Interferometry (DI) combines high spectral and high spatial resolution. On non resolved objects, it yields the angular variation of the source photocenter as a function of wavelength which has been shown theoretically and experimentally to complement very usefully both interferometric and spectroscopic data in a large number of astrophysical problems. This paper presents the general characteristics of DI which are likely to allow improvements of the Doppler images of stellar surface structures as soon as interferometers with large apertures and baselines approaching 100 m are available.

In experiments with neutral beam injection at the early stage of a Globus-M discharge, instabilities were observed that were excited by fast ions in the frequency range of 50–200 kHz, which were identified as toroidal Alfvén eigenmodes (TAE) (Petrov et al., Plasma Phys. Rep., vol. 37, 2011, pp. 1001–1005). In contradiction with the NSTX and MAST tokamaks, a regime of TAE generation was realized with strongly developed single modes. Magnetic measurements with fast Mirnov probes have shown that most of the modes have toroidal number
$n=1$
. The influence of the modes on the fast particle confinement was recorded by means of a tangentially directed neutral particle analyser (NPA) and neutron detector. Hydrogen and deuterium were used as target plasma and injected beam for study of the isotopic effect. At deuterium injection into the deuterium plasma, TAE led to the neutron rate dropping by 25 %, whereas NPA fluxes of high energy dropped by 75 %. At hydrogen injection, the drop in the measured NPA fluxes did not exceed 25 %.

It is proposed that transit observations on the islands of Spitsbergen (φ = 78°) and Ross (φ=− 78°) be organised in order to determine absolute right ascension by observing continually throughout the polar night.

How the Milky Way has accumulated its mass over the Hubble time, whether significant amounts of gas and stars were accreted from satellite galaxies, or whether the Milky Way has experienced an initial gas assembly and then evolved more-or-less in isolation is one of the burning questions in modern astronomy, because it has consequences for our understanding of galaxy formation in the cosmological context. Here we present the evolutionary model of a Milky Way-type satellite system zoomed into a cosmological large-scale simulation. Embedded into Dark Matter halos and allowing for baryonic processes these chemo-dynamical simulations aim at studying the gas and stellar loss from the satellites to feed the Milky Way halo and the stellar chemical abundances in the halo and the satellite galaxies.

Poultry biodiversity conservation is a great challenge for many countries. Within the last several years, the number of endangered local breeds has increased, leading to a considerable loss of genetic resources. A similar trend was observed among the poultry breeds, including chicken, local turkey and goose breeds/lines established in Bulgaria, part of which is definitely lost. Currently these breeds/lines are at risk and/or threatened with extinction. The information obtained by phenotypic characterization of these breeds is the first step for planning the management of poultry genetic resources through setting up improved selection schemes and conservation strategies. In this paper, we reviewed the current state of knowledge regarding the morphological and phenotypic diversity of local poultry breeds and some old productive poultry lines in Bulgaria.

Mild cognitive impairment (MCI) is characterized by subjective and objective memory impairments in the absence of manifest functional decline. Mild changes in activities of daily living (ADL) can be present and probably predict conversion to dementia. A new advanced (a)-ADL tool was developed, evaluating high-level activities and, taking each participant as their own reference, distinguishing a global Disability Index (a-ADL-DI), a Cognitive Disability Index (a-ADL-CDI), and a Physical Disability Index (a-ADL-PDI), based on the number of activities performed and the severity and causes of the functional problem. This study evaluates the discriminative validity of the a-ADL in MCI.

Method:

Based upon clinical evaluation and a set of global, cognitive, mood, and functional assessments, 150 community-dwelling participants (average age 80.3 years (SD 5; 66–91)) were included and diagnosed as (1) cognitively healthy participants (n = 50); (2) patients with a-MCI (n = 48), or (3) mild to moderate AD (n = 52). The a-ADL tool was not a part of the clinical evaluation.

Results:

The a-ADL-DI and the a-ADL-CDI showed a sensitivity and specificity ranging from 70% to 94.2%, Positive Predictive Value ranging from 70% till 93.8%, and Negative Predictive Value from 64.4% and 93.8%, an area under the curve (AUC) ranging from 0.791 to 0.960. Functional decline related to physical deficits, as assessed by the a-ADL-PDI, did not discriminate between the different groups.

Conclusion:

The a-ADL tool has a good ability to distinguish normal and pathological cognitive aging. Its discriminative power for underlying causes of limitations may be an advantage.

The sorption of Sr2+ ions by natural clinoptilolite was investigated using the batch method. The effects of pH, contact time and strontium concentrations were tested and the optimal conditions for sorption were determined. The process was very fast initially and equilibrium was reached within 24 h. Kinetic sorption data were fitted to pseudo-first-order, pseudo-second-order and intra-particle diffusion models. The simple pseudo-second-order rate model provides good agreement with the experimental data for Sr2+ uptake. The respective rate constants, k2, calculated at different initial Sr2+ concentrations, were obtained. The equilibrium data were analysed by applying the Langmuir, Freundlich and Dubinin–Raduchkevich isotherm models. The Langmuir model describes the observed Sr2+ uptake most accurately and the value of the monolayer sorption capacity is 32.81 mg Sr2+/g. The effect of Na+ ions and the effectiveness of uptake from low saline groundwater simulated solutions were also studied and discussed.

The application of natural fertilizer mixtures that improve nutrient retention ability of soils has attracted considerable attention in recent years. In addition to rock phosphate (RP), the basic components of these mixtures are zeolites modified with selected cations, such as the ammonium ion. The NH4-zeolite serves as a carrier of nutrients as well as a soil conditioner, and it promotes the RP dissolution in all soil types. The purpose of the present work was to prepare costeffective NH4-zeolite supplement, using 32 full factorial experimental designs, with concentration of modifier and processing time as variables. Saturation processes were carried out on two types of natural zeolites, K- clinoptilolite (K-Cp) and Ca-clinoptilolite (Ca-Cp). The Response Surface Method (RSM) was applied for evaluation of cation exchange, suggesting an effective NH4+ modification of natural zeolite at lower quantities of modifier than commonly found in other studies on the topic. Using Principal Component Analysis (PCA), differences between samples relative to the process variables were clearly outlined and correlated with concentrations of the exchanged cations. The best results were obtained for the K-Cp type modified with 1.5 M solution of ammonium sulfate (at a Cp/NH4+ stochiometric ratio 1:7.5) for all three processing intervals. By optimizing the modification process parameters, an experimental design of partially saturated NH4-Cp supplement that has the potential to supply all major plant nutrients was proposed.

Following an initiative taken by the Russian Ministry of Natural resources and Ecology and by the Federal Agency of Mineral Resources (Rosnedra) in 2003 international cooperation on compiling a new generation of circum-Arctic geological and geophysical maps (in scale 1: 5 000 000) was undertaken by a consortium of national agencies from Canada, Denmark, Finland, Norway, Russia, Sweden and the USA. The polar stereographic maps include onshore and offshore geological coverage to 60° N. The bedrock map and database was first published in 2008, the geophysical maps were completed in 2010, while a tectonic map is currently in press. The new circum-Arctic maps are formally published under the Comission for the Geological Map of the World (CGMW/CCGM). A metallogenic map and database of the main occurrences of onshore and offshore metal deposits is scheduled to be completed in 2016.

The implicit 2D3V particle-in-cell (PIC) code developed to study the interaction of ultrashort pulse lasers with matter [G. M. Petrov and J. Davis, Computer Phys. Comm. 179, 868 (2008); Phys. Plasmas 18, 073102 (2011)] has been parallelized using MPI (Message Passing Interface). The parallelization strategy is optimized for a small number of computer cores, up to about 64. Details on the algorithm implementation are given with emphasis on code optimization by overlapping computations with communications. Performance evaluation for 1D domain decomposition has been made on a small Linux cluster with 64 computer cores for two typical regimes of PIC operation: “particle dominated”, for which the bulk of the computation time is spent on pushing particles, and “field dominated”, for which computing the fields is prevalent. For a small number of computer cores, less than 32, the MPI implementation offers a significant numerical speed-up. In the “particle dominated” regime it is close to the maximum theoretical one, while in the “field dominated” regime it is about 75-80 % of the maximum speed-up. For a number of cores exceeding 32, performance degradation takes place as a result of the adopted 1D domain decomposition. The code parallelization will allow future implementation of atomic physics and extension to three dimensions.

This review article provides the state-of-art research and developments of the rectenna device and its two main components – the antenna and the rectifier. Furthermore, the history, efficiency trends, and socioeconomic impact of its research are also featured.

The rectenna (RECTifying antENNA), which was first demonstrated by William C. Brown in 1964 as a receiver for microwave power transmission, is now increasingly researched as a means of harvesting solar radiation. Tapping into the growing photovoltaic market, the attraction of the rectenna concept is the potential for devices that, in theory, are not limited in efficiency by the Shockley–Queisser limit. In this review, the history and operation of this 40-year old device concept are explored in the context of power transmission and the ever increasing interest in its potential applications at terahertz frequencies, through the infrared and visible spectra. Recent modeling approaches that have predicted controversially high efficiency values at these frequencies are critically examined. It is proposed that to unlock any of the promised potential in the solar rectenna concept, there is a need for each constituent part to be improved beyond the current best performance, with the existing nanometer scale antennas, the rectification and the impedance matching solutions all falling short of the necessary efficiencies at terahertz frequencies. Advances in the fabrication, characterization, and understanding of the antenna and the rectifier are reviewed, and common solar rectenna design approaches are summarized. Finally, the socioeconomic impact of success in this field is discussed and future work is proposed.